This invention relates to emollient compositions for use in cosmetic, personal care and pharmaceutical preparations. The invention particularly relates to such emollient compositions and processes for their preparation, and more particularly to jojoba ester compositions which function as a dry carrier and vehicle for the delivery of actives such as fragrances, vitamins, medications, repellents, sun screens, cosmeceuticals (materials that combine a cosmetic and therapeutic effect) and the like.
In the field of cosmetic, personal care, and pharmaceutical products emollients are usually defined as an agent that softens or smooths the skin and which tend to reduce the roughness, cracking and irritation of the skin. This smoothing is believed to be effected by the penetration of the emollient into the surface layers of tissue, through the slight congestion induced by rubbing and massage upon application, and especially through interference with sensible and insensible water loss. The ancient Greek physician, Galen, is thought to have made one of the first emollients consisting of beeswax, spermaceti, almond oil, borax and rosewater.
Emollients tend to be bland, fatty, oleaginous substances which may be applied locally to the skin, mucous membranes, or abraded tissue. One of the benefits of emollients is their ability to exclude water-soluble irritants, air, and air-borne bacteria when a layer of emollient is present. At the present, there are numerous ingredients which function as emollients in a wide variety of products, and which ingredients may act in subtly different ways. For example, certain emollients sit on the surface of the skin and serve to impede water loss from the skin. Such ingredients are generally comprised of large molecules that form a hydrophobic barrier to help prevent water from leaving the surface of the skin. Examples of such emollients are lanolin, mineral oil, silicon derivatives and petroleum jelly.
A chief use of emollients is to provide vehicles for lipid-soluble drugs (as in balms, ointments and alcohol-based liniments). Although it has often been suggested that such emollient vehicles facilitate the transport of such drugs through the skin, it has been found that when the oil:water partition coefficient is greater than 1.0, the penetration of lipid-soluble drugs tends to be impeded. Emollient substances are commonly employed in cleansing and antiphlogistic creams and lotions. Compound ointment bases, creams, and other medical applications are also general areas of use for emollients. Amongst the more common emollient materials are castor oil, corn oil, cottonseed oil, rose water ointment, apricot kernel oil, avocado oil, grape seed oil, hazelnut oil, olive oil, sesame oil, theobroma oil, almond oil, myristyl alcohol, and recently other natural oils such as jojoba oil.
Other ingredients that have been used as emollients include a number of fatty acids derived from either plants or animal sources. Fatty acids generally comprise aliphatic hydrocarbon or other organic chains with carboxylic substituents on them, typically having between 8 and 24 carbon atoms in the chain backbone. Fatty acids are often used in creams, lotions, shaving creams, lipsticks and as pressing agents in pressed powders and blushes. Fatty acids which are used in cosmetics formulations generally include at least stearic acid, oleic acid, myristic acid and palmitic acid. Other typical fatty acids include linoleic acid, behenic acid, and other common fatty acids of the general formula CnH2n+1COOH.
Fatty alcohols are also used as emollients. They are said to be less sticky and less heavy than many other fatty materials, such as the fatty acids, and are frequently used to improve the viscosity and stability of lotions and creams. They also have utility in reactive hair dying and perming products. Examples of fatty alcohols which find use in the field of cosmetics and personal care products are cetyl alcohol, lauryl alcohol, stearyl alcohol and oleyl alcohol.
Additional examples of emollients are fatty esters. One of the best qualities of fatty esters is that they do not feel as oily to the touch as some other types of emollient fatty ingredients. Examples include isopropyl palmitate, isopropyl myristate and glyceryl stearate.
An important emollient is jojoba oil which is derived from the seed of the species Simmondsia chinensis. Jojoba is a seed oil with excellent skin feel. The oil is composed almost exclusively of wax esters, with little or no triglycerides present. A major portion of the production of jojoba oil is used by the cosmetic industry as an emollient in a variety of products.
The art of perfumery is an ancient skill with origins generally traced to the first Dynasty of Egypt, which was ruled by Menes sometime between 3500 and 500 BC. Sesame, almond and olive oils were used as solvents to extract the aromatics from vegetable materials and also as vehicles for delivery of the aromatics to the skin. Early Greek writers recorded the use of oils to xe2x80x9cfixxe2x80x9d or to retard evaporation of fragrance compounds. The early Romans showed little interest in perfumes and in fact perfumed unguents were forbidden in Rome by edict in about 188 BC. By the time Nero was Emperor in A.D. 54, the Romans had migrated into southern Italy and acquired a more intimate knowledge of the aesthetic side of life from the Greeks who occupied the area. Greeks and Romans used sesame, olive, or bean oils to extract and deliver the fragrance compounds and according to Pliny, resin and gum were added to xe2x80x9cfixxe2x80x9d the odor lest xe2x80x9cit is apt to die away and disappear with the greatest rapidity if these substances are not employed.xe2x80x9d The first alcoholic perfume base appeared in 1370 and was known as xe2x80x9cHungry Water,xe2x80x9d a name attributed to Queen Elizabeth of Hungary who first commissioned its preparation. The use of alcoholic bases to deliver fragrance compounds to the skin became the method of choice around the world. Some Middle Eastern regions still adhere to the more traditional use of sesame or olive oils as fragrance carriers.
Modern purveyors of perfumes and perfumed cosmetics have social and legal mandates to reduce the amount of Volatile Organic Compounds (VOC""s) released into the atmosphere by their products. Modem technology has also identified alcohol as an agent which dries the skin and therefore there has been a desire for xe2x80x9calcohol freexe2x80x9d cosmetic and personal care products. Additional carriers and vehicles for perfumes that are acceptable to the industry and consumers are also needed.
One of the problems with typical emollients is that the emollient itself provides a wet or oily feel to the applied areas. This can lead to an uncomfortable feeling or appearance to the user, which is very important in the cosmetic and pharmacological industry. An additive for cosmetic, personal care and topical treatment (medicament) products has been marketed under the name of xe2x80x9cConfettixe2x80x9d(trademark) (with different alphanumeric identifiers as to specific ingredients, e.g., Confetti(trademark) AL with allantion, and Confetti(trademark) EA, MT, PA, RG and SG identifying the color of the material). This material is advertised as decorative microcapsules which contribute beneficial moisturizing and delivery of alcohol soluble ingredients to the skin. Confetti(trademark) is advertised as having a good balance of structural integrity and rub-in characteristics, rubbing into the skin completely without any extra pressure. The Material Safety Data Sheets (MSDS) on Confetti IMproducts identifies them as containing a natural oil (e.g., coconut oil, tocopheryl acetate, retinyl palmitate), propylene glycol, synthetic beeswax, petrolatum, allantion, PVM/MA Decadiene crosspolymer and benzophenone, as well as pigments and/or dyes.
Jojoba ester compositions have been found to finction well as a dry carrier or vehicle for the application of active materials to the skin or hair of customers. These esters have been found to be useful in pure or blended forms as carriers or vehicles in the personal care, cosmetic, and/or pharmaceutical fields of use. The esters to be used may be provided with a range of properties (from the composition of the ester itself or from additives and blended materials) and can provide improved feel when used with other conventional carriers, vehicles, bases, actives and additives. Upon application and xe2x80x98rubbing inxe2x80x99 of the compositions, the jojoba ester based compositions leave the skin feeling soft (which is typical of high quality emollients), yet provide a mildly persistent coating which carriers the actives without leaving a wet or oily feel to the skin of the user.
The present invention describes a very effective dry-feel emollient composition additive for use in personal care, cosmetic and pharmaceutical products and a novel method of producing that composition. The composition is essentially solid at room temperature, can be provided in various shapes and sizes (especially as spheres), and can be produced from combinations of fatty alcohols, isopropyl esters and wax esters obtained from the oil contained in the seed of the jojoba plant (Simmondsia chinensis), jojoba oil.
These new emollient compositions preserve the excellent skin feel attributed tojojoba oil, which has long been used as an emollient. These new compositions also increase the range of applications for cosmetic compositions through an emollient that is more polar and hydrophilic than is found in jojoba oils, (which may also be referred to in the art as jojoba wax esters). The composition forms stable emulsions much more readily than does jojoba oil. The composition may also further provide excellent emolliency to normally dry cosmetic systems involving high levels of pigments, with the emollient acting as a pigment wetting agent and as an aid to a smooth and even application of the dry system. It also functions as an excipient in pressed powder.
The compositions comprising fatty alcohols, isopropyl esters and jojoba wax esters (jojoba oil) may be obtained by the base catalyzed alcoholysis reaction between jojoba oil and an alkyl alcohol. In the alcoholysis reaction, examples of the base catalyst materials include, but are not limited to metal alkoxides and especially alkali metal alkoxides, inorganic hydroxides, especially alkali metal hydroxides, and the like such as NaOCH3 sodium methoxide, NaOCH2CH3 sodium ethoxide (potassium, calcium and lithium counterparts), KOH and NaOH (e.g., anhydrous alkali metal hydroxides in alcohol solution, with the alcohol of the solution being the alcohol used in the reaction).
The findamental reactions used in the practice of the present invention may be generally considered in the following manner. Starting materials could include:
I. The alcohol,
R4xe2x80x94OH (with isopropyl alcohol (IPA, HOxe2x80x94CHxe2x80x94(CH3)2) being primarily emphasized),
II. Jojoba Wax Esters
R1xe2x80x94COOxe2x80x94CH2xe2x80x94R1, and
III. Fully hydrogenated Jojoba Wax Esters
R2xe2x80x94COOxe2x80x94CH2xe2x80x94R2 
xe2x80x83wherein R4 is an alkyl group or other aliphatic group, preferably of 1 to 12 carbon atoms, more preferably an iso-alkyl group, and most preferably an isopropyl group,
R1 comprises CH3xe2x80x94(CH2)7xe2x80x94CHxe2x95x90CHxe2x80x94CH2xe2x80x94(CH2)xxe2x80x94, and
R2 comprises CH3xe2x80x94(C2)yxe2x80x94
xe2x80x83wherein x is 6, 8, 10 and/or 12, and y is 16, 18, 20 and/or 22.
R4 comprises CnH2n+1xe2x80x94, wherein n=1 to 12.
Typical product components from the preferred synthetic reactions used in the practice of the present invention with jojoba oil may include:
Partially saturated wax esters:
IV. R1xe2x80x94COOxe2x80x94CH2xe2x80x94R2 and/or V.R2xe2x80x94COOxe2x80x94CH2xe2x80x94R1.
xe2x80x83(Where isopropyl alcohol was used) iso-propyl esters
VI. R1xe2x80x94COOxe2x80x94CHxe2x80x94(CH3)2 [generically R1xe2x80x94COOxe2x80x94R4] and/or
VII. R2xe2x80x94COOxe2x80x94CHxe2x80x94(CH3)2 [generically R2xe2x80x94COOxe2x80x94R4] and fatty alcohols comprising
VIII. R2xe2x80x94COOxe2x80x94CHxe2x80x94(CH3)2[generically R2xe2x80x94COOxe2x80x94R4] and
The basic reactions which may be used in the preparation of the emollient compositions of the invention derived from jojoba oil may include at least the following procedures.
Reaction A I and IIn (catalyst)xe2x86x92VI, VIII and IIr. This product is referred to herein as xe2x80x9cFloraesters-IPTxe2x80x9d and is a liquid.
Reaction B I and IIIN (catalyst)xe2x86x92VII, IX and IIIr. This product is referred to herein as xe2x80x9cFloraester-HIPJxe2x80x9d and is a solid.
Reaction C I, and IIn and IIIn (catalyst)xe2x86x92IV, V, VI, VII, VIII, IX, IIr and IIIr. This product is referred to herein as xe2x80x9cthe broad melting range emollientxe2x80x9d and the properties of the emollient depend upon the relative amounts of IIn and IIIN.
The subscripts n and r respectively represent n=the naturally occurring distribution of wax esters and r=the randomized distribution of wax esters resulting from rearrangements which occur during the reactions. It is to be noted that mixing of the reaction products from A and B will give emollients with a wide range of melting points, but will not be identical to the reaction product of C because of the absence of IV and V.
A process for producing an emollient may comprise the steps of:
a) providing a composition comprising jojoba oil,
b) adding an alcohol, e.g., having from 1 to 12 carbon atoms, to said composition,
c) effecting alcoholysis on said jojoba oil mixed with said alcohol to produce an emollient, and
d) effecting interesterification of remaining wax esters.
In preparing the emollient composition, refined jojoba oil (or hydrogenated jojoba oil or a mixture of the oil and hydrogenated oil) is introduced into an appropriate vessel (capable of excluding air) equipped with stirring and means of heating and cooling. The jojoba oil is first dried under vacuum at a temperature of 90 C to remove most or all moisture. The anhydrous isopropyl alcohol (or other alcohol) is then added with the amount of isopropyl used being from about 20% to about 50% by weight ofjojoba oil. The reactor is sealed and heat is applied to bring the temperature of the reaction mixture to about 70-75xc2x0 C. It is important that air be excluded and that the reactor be vented through a condenser to recover any unreacted alcohol. When the temperature has reached 70-75xc2x0 C., a first addition of catalyst (e.g., a catalyst for alcoholysis and interesterification such as sodium methoxide) is made. The amount added ranges from about 0.05 or from 0.1% to about 0.6% by weight of the jojoba oil with about 0.3% being preferred. After about 2 hours, a sample is taken and analyzed for the presence of the wax esters. If the wax ester content is greater than about 25% by weight, and it is desired to have a lower level of wax esters present in the reaction mixture, a second addition of catalyst is made, about 0.1% by weight of the original amount of jojoba oil. The reaction is then continued for an additional one hour. The reaction mixture is then sampled and analyzed again. If the residual wax ester content is less than about 25-35%, the reaction may be considered to be complete. Heating is discontinued but no cooling is applied. If the reaction is considered incomplete, a third catalyst addition may be made and the reaction continued as previously described. Any remaining catalyst can be neutralized and deactivated by the addition of citric acid. After about 15 minutes of agitation the neutralized catalyst (sodium citrate) is removed by filtration. Once the catalyst has been removed, any remaining isopropyl alcohol can be distilled from the product and the recovered isopropyl alcohol should be kept absolutely dry in order to be able to be used again.
As used in this description of the present invention, Floraesters 70 is III, Floraesters 15 is IIr, Floraesters 20, 30 and 60 are combinations of IIr, IV, V, and IIIr, Floraesters IPJ is a mixture of IIr, VI, and VIII, and Floraesters HIPJ is a combination of IIIr, VII and IX.